How many deck boards for a 8x8 deck?
You need 18 deck boards at 8 ft long.
That is 18 rows across the 8 ft span, or 144 linear feet. Buy 159 linear feet to cover the usual 10% for cuts and defects.
A 8x8 deck by the numbers
| Deck area | 64 sq ft |
|---|---|
| Rows of decking | 18 |
| Board length | 8 ft |
| Boards to buy | 18 |
| Decking | 144 linear ft |
| With 10% waste | 159 linear ft |
| Joists at 16 in on centre | 7 |
| Footings | 4 |
| Deck screws | 324 |
Where that number comes from
- 8 ft across × 12 = 96 in to cover
- 96 ÷ 5.625 = 17.1 rows, rounded up to 18
- 18 rows × 8 ft long = 144 linear feet
- Add 10% for cuts and culls = 159 linear feet
Boards run the length of the deck here, so the 8 ft dimension sets board length and the 8 ft dimension sets how many rows you need. Running them the other way swaps the two numbers.
Working to a different size? The calculator takes any dimensions and returns the same figures.
Cutting a 8x8 out of stock lengths
The 8 ft run lands exactly on a 8 ft board: 18 boards, 18 rows, nothing cut and nothing left over. Why running them the other way changes the order.
Worth pricing the alternative: a 16 ft board cuts into exactly two 8 ft rows, so 9 of them covers the same deck. Half the pieces to carry and handle, and long stock is often slightly cheaper by the foot. Against that, 16 ft boards need a truck and one bad cut wastes two rows instead of one.
Order 159 linear feet, not the bare 144 — about 2 spare rows on a 8x8. What the cull rate covers.
Before you order: getting a decking order right.
Other deck sizes
Deck calculator for any size, or all calculators.